A host of health problems are associated with consumption of refined sugar. Sauces such as ketchup, mayonnaise... contained higher level of refined sugar. Using behavioural influence techniques it could be possible to encourage consumer to reduce their consumption of refine sugar. In this study, the mirror exposure procedure was used in order to decrease students’ sauces consumption in a university cafeteria. A mirror was stand or not in a self-service area with various sauces (mayonnaise, ketchup, mustard). People were unobtrusively observed and noticed which of the sauces was taken by each customer and the number of times the customer pressed on the sauce dispenser in order to obtain one dose of sauce. In the mirror exposure, the observers noted if the customer looked at the mirror when using the sauce dispenser. Results showed a decrease in consumption but only with individuals who look at them when using the sauce-dispensers. In a field setting, it was found that the mirror technique is an efficient method to decrease sauce consumption, and by extension, the consumption of refined sugar. The practical and the theoretical interest of this procedure are discussed.